Mitsubishi GOT 1000 GT16, User Manual

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10.2 Troubleshooting in Bus Connection
10.2 Troubleshooting in Bus Connection
When connect GOT and PLC CPU with bus connection, and the cause is not clear in "10.3.2 List of error message/
system alarm", execute the following troubleshooting.
Refer to the following for details concerning the bus connection.
•GOT1000 Series Connection Manual (Mitsubishi Products) for GT Works3
•GOT1000 Series Connection Manual for GT Designer2/GT Works2
10.2.1 Locating error positions
Explanation regarding the method of specifying the error part.
(Please refer to User's Manual of used PLC CPU for details related to the PLC CPU error and special register.)
(1) How to locate error positions:
(a) Use of peripheral devices
Using the peripheral devices such as GX Developer, check what type of the error occurs on the PLC CPU
and, based on the error message on the PLC CPU, check each module and cable for installation and
earthing statuses.
(b) Error timing
Check the timing of errors.
(c) Locating the module where an error occurs:
Based on the PLC CPU error codes and special resister information, locate a specific module where an
error occurs.
By the method stated above, correct the sequence program or replace the faulty module with a new one, and
check whether the error occurs.
If the error continues to occur, it may have another cause.
Referring to "10.2.2 Further locating error positions", locate the error position further.
1) An error occurs when the power is turned on or immediately after the PLC is reset:
The error may be detected by the initial processing of the PLC CPU.
In this case, because the faulty module may not be identified, use only an END instruction for the
sequence program and remove the modules one by one until the error does not occur.
When the error is eliminated after a specific module has been removed, the module may be
causing the error.
2) An error occurs after a specific operation or several seconds:
The error may occur in the sequence program. Check the error step where the error may occur
and the sequence program in that step.
The sequence program can be diagnosed throughout by merely using an END instruction for the
sequence program.
3) An error occurs when a specific device operates:
The mis-operation may be caused by noise.
Check that any signal line such as bus cable is not laid out too close to the operating device. If the
line is too close to the device, separate the line 100 mm or more from the device.